The present invention relates to a system and method for heating and/or cooling a building structure, for distribution and storage of heat within a building structure, and for economically controlling temperature within a building structure.
It has long been known that windows create particular problems not only in economically heating a building in winter and cooling in summner, but also in the control of the temperature in different parts of the building. One reason is that the windows generally have poorer insulating qualities in comparison with the walls of the building structure. In winter, not only does this give rise to excessive heat losses, but the formation of cold air adjacent the window causes unwanted drafts in a room.
In summer conditions, the problem is reversed. The sun's radiation penetrates the windows, and this makes it necessary to circulate air through the room or install mechanical cooling systems to avoid high room temperatures. In many cases the required cooling effect is so high that drafts from fast moving room air will result.
A number of years ago, the "extract-air window" system was developed to alleviate to a substantial extent these problems in that it can take care of a large proportion of the work normally done by customary heating and cooling systems. In this system, the window structure is formed as a pair of spaced panels, namely an exterior panel (usually a double window pane for better insulation) and an interior panel that is spaced from the exterior panel so as to provide a plenum between the two panels. Within the plenum is a set of blinds, which can be in the form of conventional Venetian blinds. At the lower part of the inner panel, there is a lower air intake opening so that room air (i.e. air from within the building) enters into this opening, passes upwardly through the plenum, and through an upper outlet opening to be recirculated in the building or discharged to outside atmosphere (or a combination of these).
There are a number of advantages to this arrangement. Let us take the example where the outside temperature is relatively cool, with the sun shining on one side of the building, while the other side of the building remains in the shade. Without the window arrangement described above, the radiation from the sun would normally pass through the window to heat the room on the sunny side of the building. If there are people in the room, artificial lighting, equipment that uses power, etc., yet more heat is generated. Thus, even though the outside temperature might be lower than the desired temperature inside the building, it still becomes necessary to cool the room having windows exposed to direct sunlight.
With the extract-air window system, much of the solar radiation is absorbed by the blinds within the plenum of the window structure. The air from the room is circulated upwardly through the plenum to absorb the heat from the blinds, and this air can be circulated to the opposite side of the building that is shaded from the direct solar radiation. The interior air at the shady side of the building (which would likely be somewhat cooler) can be recirculated back to the sunny portion of the building.
With regard to the extract-air window structure on the shady side of the building, this also has advantages. With circulation of the room air upwardly through the window structure plenum, this substantially eliminates the drafts that might otherwise occur if the temperature adjacent the window structure were permitted to drop too far below the temperature of the air in the remaining part of the room.
Also, during cold weather the extract-air window system can be used advantageously to store energy in the building structure itself in a manner to reduce heating costs. For example, during the daytime, room air can be circulated through the window structure that is exposed to the sun to extract heat from the blinds within the window structure. This heated air can then be circulated through a heat exchange structure that can be made as a hollow core slab that functions also as the floor and ceiling structure. Since the temperature in the plenum of the window structure can be reaised to as high as 20.degree. to 80.degree. F. above the interior room temperature, it becomes readily apparent that substantial heat transfer could take place between this air and the heat retaining structure. Then, in the nightime, air can be recirculated through the slab structure to extract heat therefrom and prevent the temperature in the building from dropping excessively. Then, in the morning, when it is desired to raise the building temperature to the desired level, less energy is required. Even though the blinds in the window provide a shield for the solar radiation, a substantial amount of the visible light is permitted to pass into the room.
The extract-air window system can be used advantageously to cool the building in the summer time. With regard to the window structure that is exposed to direct solar radiation, the room air can be circulated through the window structure to absorb heat and be discharged to the outside atmosphere so as to dissipate the effects of the solar radiation. Also, the hollow heat exchange slab structure can be used to absorb excessive heat in the building in the daytime. This is accomplished by first circulating cool nightime air through the circulation system to reduce the temperature of the heat exchange slab structure. Then, during the day, the room air is cooled by being circulated through the heat exchange slab structure.
The extract-air window system has been described in several publications, namely: a paper entitled "Extract-Air Window, a Key to Better Heat Economy in Buildings", presented at the Tenth World Energy Conference, Istanbul, Sept. 19 to 23, 1977; a paper entitled "Extract-Air Window as a Solar Collector and Hollow-core Concrete Slab as a Heat Utilizer", presented at the VVS 78 Conference, Stockholm Sweden, May 18, 1978; and a pamphlet entitled "The EKONO-HOUSE Energy Efficiency", published by Econo Consuoting Engineers, P.0. Box 27, 00131, Helsinki 13, Finland.
A search of U.S. patent literature disclosed a number of U.S. patents relating generally to heat exchange systems utilizing window structures and heat storage components in the building.
U.S. Pat. No. 3,050,443 shows a multi-paned window in which air is passed between the panes so that it can be heated by solar energy. Between the panes is placed either a heat-absorbing plate, or a venetian blind which absorbs or reflects the energy as needed.
U.S. Pat. No. 4,002,159 shows a venetian blind system that is placed in front of a window which creates a channel for air to be heated by solar energy.
U.S. Pat. No. 3,990,635 discloses a window with an air space. There is ducting above and below the window for passage of heated air.
U.S. Pat. No. 3,925,945 shows a window with air space that is used to heat air. There are vents so that the air can be passed into the room or to the outside as needed.
U.S. Pat. No. 3,012,294 relates to a window with a shutter which controls the amount of light that can pass. The shutter is made so that there is a good air seal.
U.S. Pat. No. 2,931,578 shows a device added to the window so that it can serve as an air heater.
U.S. Pat. No. 246,626 shows a window-like device added to the side of a building, vented into the room for heating it.
U.S. Pat. No. 4,147,300 relates to a system where air is heated in a hollow wall and passes through ducts to other parts of the building. The mass of the wall also serves as a heat storing means.
U.S. Pat. No. 4,069,973 discloses slabs that have ducts for heated or cooled air. This also acts as a heat storage means.
U.S. Pat. No. 4,069,971 discloses a system where air is ducted by passages within the wall which again stores heat.
In U.S. Pat. No. 4,006,856, there is a solar collector at the roof. The heated air is passed through the walls to storage mass under the floor.
In U.S. Pat. No. 2,877,990, there are ducts mounted in floor/ceiling slabs which carry air.
U.S. Pat. No. 2,559,869 discloses air passages in the walls. There is some solar collection such as through panel 19 on the roof.
In U.S. Pat. No. 1,065,762 there are hollow blocks used for air passages so as to ventilate the building, walls and basement.
Finally, U.S. Pat. No. 180,841 shows ventilating passages within the walls of a building.